PLANT PROTECTION

B. Diseases

The coconut palm is affected by a number of diseases, some of which are lethal while others gradually reduce the vigour of the palm causing severe loss in yield. A brief account of the important coconut diseases is given.

VI. Mahali

	Symptoms  Shedding of female flowers and immature nuts. Lesions appear on the young fruits or buttons near stalk which later result in decay of the underlying tissues.
Control measures  Spray 1% Bordeaux mixture on the crown of the palm once before the monsoon and later after 40 days interval. Remove and destroy fallen nuts. In dwarf palms, apply Dithane M-45 in place of Bordeaux mixture.

VII. Crown Chocking

Symptoms

1. Characterised by emergence of shorter leaves with fascinated and crinkled leaves.
2. The leaflets show severe tip necrosis and fail to unfurl. In many cases, it gives a choked appearance to the frond.
3. Ultimately the affected palm dies.

Control measures

1. Application of 50 g Borax at half-yearly intervals (Feb-Mar and Sept-Oct) along with recommended fertilizer in the basins will control the disease when it is in the early stage. In root wilt affected areas a dosage of 200gm - 300gm per palm per year is recommended.

VIII. Leaf blight or Grey Leaf Spot

Symptoms

1. Minute yellow spots encircled by greyish bands appear on the surface of mature leaves of the outer whorl.
2. Later they become greyish white. These spots coalesce into irregular necrotic patches.
3. Complete drying and shrivelling of the leaf blade are common when the infection is severe.

Control measures

1. Removal of the older 2-3 disease affected leaves and spraying the foliage with 1% Bordeaux Mixture will check the spread of the disease.

IX. Tatipaka Disease

Symptoms

1. First appeared in Tatipaka village of East Godavari district of Andhra Pradesh, following a cyclone in 1949. Palms in the age group of 25 to 60 years are more susceptible.
2. Development of an abnormally large crown with dark green inner leaves and higher yield is the precursor of disease incidence. Subsequently the crown becomes smaller in size producing progressively shorter leaves.
3. The stem begins to taper. The leaves give a fascinated appearance due to improper unfolding of leaflets. The affected tree produces smaller bunches with atrophied barren nuts.
   The causal agent is suspected to be Phytoplasm.

For details regarding Pests of Coconut click here: Pests

For more details please contact us: 

E-mail: kochi.cdb@gov.in